U.S. patent application number 10/756635 was filed with the patent office on 2005-07-14 for mobile vehicle sensor array.
Invention is credited to Jacobs, Steven.
Application Number | 20050154503 10/756635 |
Document ID | / |
Family ID | 34739880 |
Filed Date | 2005-07-14 |
United States Patent
Application |
20050154503 |
Kind Code |
A1 |
Jacobs, Steven |
July 14, 2005 |
Mobile vehicle sensor array
Abstract
An improved sensor array for a mobile vehicle. More
particularly, the primary objective of the present invention is to
provide mobile vehicle (10) traveling in a forward direction with a
sensor array (12). Sensor array (12) comprises a first sensor (16)
mounted to mobile vehicle (10) at a maximum lateral distance from
said vertical axis of rotation (21) near a first side of mobile
vehicle (10) and a second sensor (18) mounted to mobile vehicle
(10) at a maximum lateral distance from said vertical axis of
rotation (21) near a second side of mobile vehicle (10). First
sensor (16) and the second sensor (18) emit object detecting beams
for detecting an object (39) ahead of mobile vehicle (10). A
plurality of other object detecting beams are emitted obliquely to
the object detecting beams of sensor (16) and sensor (18). These
other beams, in conjunction with the object detecting beams from
sensor (16) and sensor (18) form zones of overlapping beam coverage
for better detection of objects.
Inventors: |
Jacobs, Steven; (Monterey,
CA) |
Correspondence
Address: |
LaRiviere, Grubman & Payne, LLP
P.O. Box 3140
Monterey
CA
93942
US
|
Family ID: |
34739880 |
Appl. No.: |
10/756635 |
Filed: |
January 12, 2004 |
Current U.S.
Class: |
701/1 ;
701/96 |
Current CPC
Class: |
G05D 1/0242 20130101;
G05D 1/024 20130101 |
Class at
Publication: |
701/001 ;
701/096 |
International
Class: |
G06F 007/00 |
Claims
I claim:
1. A sensor array for a mobile vehicle, having a front, a first
side, a second side, and a vertical axis of rotation and traveling
in a forward direction comprising: a plurality of sensors disposed
generally along said front of said mobile vehicle emitting a
plurality of object detecting beams, said plurality of sensors
including a first sensor disposed at a maximum lateral distance
from said vertical axis of rotation near the first side for
emitting a first object detecting beam ahead of said mobile
vehicle; and a second sensor disposed at a maximum lateral distance
from said vertical axis of rotation near the second side for
emitting a second object detecting beam ahead of said mobile
vehicle.
2. A sensor array for said mobile vehicle of claim 1, wherein said
first sensor and said second sensor mounting further includes
recessing at least one of said first sensor and said second sensor
within a periphery of said mobile vehicle.
3. A sensor array for said mobile vehicle of claim 1, further
comprising a third sensor, which said third sensor is disposed in
said mobile vehicle adjacent to said first sensor, obliquely emits
a third object detecting beam that overlaps with said first object
detecting beam to create an overlapping beam zone for detecting
objects.
4. A sensor array for said mobile vehicle of claim 3, further
comprising a fourth sensor, which said forth sensor is disposed in
said mobile vehicle adjacent to said second sensor, obliquely emits
a fourth object detecting beam that overlaps with said second
object detecting beam to create an overlapping beam zone for
detecting objects ahead of said mobile vehicle direction of
travel.
5. A sensor array for said mobile vehicle of claim 4, wherein said
overlapping beam zones are computed by sensor fusion software to
provide an increased a confidence interval for detecting said
object.
6. A sensor array of claim 1, wherein said first sensor and said
second sensor are selected from a group consisting of piezoelectric
sensors, electrostatic sensors, magnetorestrictive sensors,
infrared sensors and light detecting and ranging (LIDAR)
sensors.
7. A sensor array of claim 1, wherein said first sensor and said
second sensor mounting includes positioning said first sensor
recessed within a first acoustically tapered matching network and
said second sensor recessed within a second acoustically tapered
matching network.
8. A sensor array of claim 7, wherein said first acoustically
tapered impedance matching network comprises a first conically
tapered horn and said second acoustically tapered impedance
matching network comprises a second conically tapered horn.
9. A sensor array of claim 7, wherein said first acoustically
tapered impedance matching network comprises a first conically
shaped horn that transitions a small piston diameter acoustical
beamwidth radiating from said first sensor and to a larger piston
diameter acoustical beam, and said second acoustically tapered
impedance matching network which comprises a second conically
shaped horn that transitions a small piston diameter acoustical
beamwidth radiating from said second sensor to a large diameter
acoustical beamwidth.
10. A sensor array of claim 1, wherein said plurality of sensors
are symmetrically spaced-apart sensors that are mounted to said
mobile vehicle, wherein symmetrically spaced-apart sensors are
located in a same plane.
11. A sensor array of claim 1, wherein said plurality of sensors
are symmetrically spaced-apart sensors that are mounted to said
mobile vehicle, wherein symmetrically spaced-apart sensors are
located in different planes.
12. A sensor array of claim 1, wherein said plurality of sensors
are asymmetrically spaced-apart sensors that are mounted to said
mobile vehicle, wherein asymmetrically spaced-apart sensors are
located in a same plane.
13. A sensor array of claim 1, wherein said plurality of sensors
are asymmetrically spaced-apart sensors that are mounted to said
mobile vehicle, wherein asymmetrically spaced-apart sensors are
located in different planes.
14. A sensor array as in claims 10, 11, 12, or 13, wherein said
symmetrically spaced-apart sensors comprise sonar sensors each
emitting a beamwidth within the range of approximately 12 degrees
to approximately 15 degrees.
15. A sensor array as in claims 10, 11, 12, or 13, wherein said
symmetrically spaced-apart sensors comprise laser ranging
sensors.
16. A sensor array as in claims 10, 11, 12, or 13, wherein said
spaced-apart sensors for said mobile vehicle comprising a
rectangular shape with rounded corners are configured in a U-shaped
arrangement.
17. A sensor array as in claims 10, 11, 12, or 13, wherein said
spaced-apart sensors for said mobile vehicle are configurable to
suit the shape of said front of said mobile vehicle.
18. A method for controlling a direction of travel of a mobile
vehicle having a front, a first side, a second side, a vertical
axis of rotation, and traveling in a forward direction comprising:
mounting a first sensor to said mobile vehicle at a maximum lateral
distance from said vertical axis of rotation near the first side;
mounting a second sensor to said mobile vehicle at a maximum
lateral distance from said vertical axis of rotation near the
second side; emitting a first object detecting beam from said first
sensor ahead of said mobile vehicle; emitting a second object
detecting beam from said second sensor ahead of said mobile
vehicle; and illuminating an object directly ahead of said front of
said mobile vehicle.
19. A method for controlling direction of travel of said mobile
vehicle of claim 18, wherein said first sensor and said second
sensor mounting further includes recessing at least one of said
first sensor and said second sensor within a periphery of said
mobile vehicle.
20. A method for controlling the direction of travel of said mobile
vehicle of claim 18, further comprising the steps of: mounting a
third sensor to said mobile vehicle along a center of said front of
said mobile vehicle; mounting a fourth sensor to said left of said
third sensor along said mobile vehicle periphery; emitting an
object detecting beam from said fourth sensor, whereby said object
detecting beam from said fourth sensor intersects with said object
detecting beam from said first sensor to create an first
overlapping beam zone; mounting a fifth sensor to said left of said
fourth sensor along said mobile vehicle periphery; emitting an
object detecting beam from said fifth sensor, whereby said object
detecting beam from said fifth sensor intersects with said object
detecting beam from said first sensor to create a second
overlapping beam zone; and detecting an object ahead at said left
forward edge of said mobile vehicle, whereby a confidence interval
of increasing value is created depending the number of overlapping
beam zones said object is detected within.
21. A method for controlling the direction of travel of said mobile
vehicle of claim 18, further comprising the steps of: collecting
data coverage about the location of said object; and processing
said data using fusion software.
22. A method for controlling direction of travel of said mobile
vehicle of claim 18, further including the step of mounting
spaced-apart sensors along said mobile vehicle to provide more than
two overlapping beam zones, wherein said spaced-apart sensors are
configurable to provide scanning area coverage selected from a
range of approximately 190-degrees to approximately 200-degrees.
Description
REFERENCE DOCUMENT
[0001] This application is related to the subject matter discussed
in Disclosure Document No. 536507 submitted on Aug. 8, 2003, to the
Commissioner for Patents entitled "Reconfigurable 195 Degree Sonar
Vision with Peripheral Vision."
TECHNICAL FIELD
[0002] This invention relates to a sensor array for a mobile
vehicle. More particularly, this invention relates to a sensor
array for a mobile vehicle traveling in a forward direction having
a first sensor and a second sensor. The first sensor is disposed on
the mobile vehicle at a maximum lateral distance from said vertical
axis of rotation near a first side. The second sensor is disposed
on the mobile vehicle at a maximum lateral distance from said
vertical axis of rotation near a second side. The first sensor
emits a first object detecting beam ahead of the mobile object. The
second sensor emits a second object detecting beam ahead of the
mobile object. The first object detecting beam overlaps with other
obliquely emitted object detecting beams from a plurality of
sensors on a front of the mobile vehicle to create an overlapping
beam coverage to detect object in the path of the mobile vehicle.
The second object detecting beam overlaps with other obliquely
emitted object detecting beams from a plurality of sensors sensor
to create an overlapping beam coverage to detect objects in the
path of the mobile vehicle.
BACKGROUND ART
[0003] Control systems for a mobile vehicle need to accurately
detect when an object is on a collision course with the mobile
vehicle. For example, the mobile vehicle may be an unmanned,
robotic cleaning machine. Prior art robotic cleaning machines have
problems detecting objects directly ahead of the cleaning machine
because sensors mounted on the cleaning machine emit beams that
don't accurately detect the presence of an object directly ahead of
the left forward and the right forward edges of the cleaning
machine. Further, prior art cleaning machines have a limited field
of vision because the sensors don't accurately detect an object's
location ahead of a cleaning machine. Other problems with prior art
cleaning machines include that the mobile vehicle transmits beams
that interfere with the received beams so that is it difficult to
detect objects close to the cleaning machines, and these mobile
vehicles have limited built-in redundancy for detecting objects
directly in the path of the cleaning machines.
[0004] As such, there is a need for an improved control system for
the mobile vehicle, which improves the mobile vehicle's detection
of the objects directly ahead of the mobile vehicle left and right
forward edges, and provides other advantages over prior art
cleaning machines such as reduced interference between transmitted
beams from the mobile vehicle and received beams widths from the
objects. Still other advantages include the mobile vehicle's
improved transmitted beam patterns so that the mobile vehicle
detects accurately the distance between the cleaning machine and
the structures it approaches, i.e., walls, and/or objects located
directly in front the mobile vehicle and at the periphery of the
sides of the mobile vehicle.
DISCLOSURE OF THE INVENTION
[0005] Accordingly, the primary objective of the present invention
is to provide an improved sensor array for a mobile vehicle. More
specifically, the present invention is a sensor array for a mobile
vehicle that travels in a forward direction, which mobile vehicle
has a front, a first side, a second side and a vertical axis of
rotation. The sensor array includes a plurality of sensors disposed
generally along said front of said mobile vehicle emitting a
plurality of object detecting beams. The sensor array comprises a
first sensor and a second sensor. A first sensor is disposed on the
mobile vehicle at a maximum lateral distance from said vertical
axis of rotation near the first side for emitting a first object
detecting beam. A second sensor is disposed on the mobile vehicle
at a maximum lateral distance from said vertical axis of rotation
near the second side for emitting a second object detecting beam.
As such, the first object detecting beam and the second object
detecting beam detect objects ahead of the mobile vehicle.
[0006] Another feature of the present invention is that the sensor
array includes recessing the sensors to provide better detection of
an object. Specifically, in one preferred embodiment of the present
invention the sensor array for the mobile vehicle has the first
sensor recess-mounted within a periphery of the mobile vehicle.
Further, the second sensor is recess-mounted within a periphery of
the mobile vehicle. A sensor array for said mobile vehicle wherein
said first sensor and said second sensor mounting further includes
recessing at least one of said first sensor and said second sensor
within a periphery of said mobile vehicle. In one preferred
embodiment, a sensor array for said mobile vehicle further
comprises a third sensor, which said third sensor is disposed in
said mobile vehicle adjacent to said first sensor, obliquely emits
a third object detecting beam that overlaps with said first object
detecting beam to create an overlapping beam zone for detecting
objects. In another preferred embodiment, mobile vehicle further
comprises a fourth sensor, which said forth sensor is disposed in
said mobile vehicle adjacent to said second sensor, obliquely emits
a fourth object detecting beam that overlaps with said second
object detecting beam to create an overlapping beam zone for
detecting objects ahead of said mobile vehicle direction of
travel.
[0007] To further improve detection of objects, an additional
feature of the present invention is that the sensor array has the
at least two overlapping beam zones where the data of the object
location is computed utilizing sensor fusion software. The fusion
software increases a confidence level for detecting the object
ahead of the mobile vehicle because as the mobile vehicle travels
toward the object, the object is detected in successive multiple
overlapping beam zones. Another feature of the present invention is
that the first and the second sensors are selected from a group
consisting of piezoelectric sensors, electrostatic sensors,
magnetorestrictive sensors, infrared sensors and light detecting
and ranging (LIDAR) sensors.
[0008] Another feature in an alternative preferred embodiment of
the present invention is providing impedance tapering for the
sensors of the array to increase the accuracy of the detection of
objects. Specifically, the sensor array further includes the first
sensor recess-mounted within a first acoustically tapered matching
network and the second sensor recess-mounted within a second
acoustically tapered matching network. In one preferred embodiment
of the present invention, the first acoustically tapered impedance
matching network comprises a first conically tapered horn and the
second acoustically tapered impedance matching network comprises a
second conically tapered horn. More specifically in one alternative
preferred embodiment of the present invention, the first
acoustically tapered impedance matching network comprises a first
conically tapered horn, wherein the first conically tapered horn
transitions a small piston diameter acoustical beamwidth radiating
from the first sensor to a larger piston diameter acoustical
beamwidth. More specifically in one alternative preferred
embodiment of the present invention, the second acoustically
tapered impedance matching network comprises a second conically
tapered horn, wherein the second conically tapered horn transitions
a small piston diameter acoustical beamwidth radiating from the
second sensor to a larger piston diameter acoustical beamwidth.
[0009] In one preferred embodiment, a plurality of sensors are
asymmetrically spaced-apart sensors that are mounted on the mobile
vehicle and that are asymmetrically spaced-apart sensors are not
located in the same plane. In another preferred embodiment, a
plurality of sensors are symmetrically spaced-apart sensors that
are mounted on the mobile vehicle and that all symmetrically
spaced-apart sensors are located in the same plane. In this
preferred embodiment of the present invention, an engineer may
custom position the plurality of sensors to maximize forward area
coverage depending on the shape of the mobile vehicle. In one
alternative preferred embodiment of the present invention, the
spaced-apart sensors comprise sonar sensors each emitting a
beamwidth within the range of approximately 12 degrees to
approximately 15 degrees. In another preferred embodiment of the
present invention, the spaced-apart sensors comprise light emitting
and ranging detectors (LIDAR) sensors.
[0010] It is another feature of the present invention that the
spaced-apart sensors may be arranged in multiple configurations to
maximize a field of vision of the mobile vehicle. In particular, in
one preferred embodiment of the present invention, the spaced-apart
sensors are configured or reconfigured in a U-shape arrangement to
achieve an approximate 195-degree field of view for a mobile
vehicle comprising a rectangular shape with rounded corners. It is
another feature of the present invention, the spaced-apart sensors
for the mobile vehicle that are configurable and reconfigurable by
a user to suit the shape of the mobile vehicle so that different
data coverage areas may be programmed into the sensor array to
maximize detection of the objects.
[0011] Further, a method for the present invention is disclosed for
controlling a direction of travel of a mobile vehicle having a
front, a first side, a second side and a vertical axis of rotation
traveling in a forward direction comprising mounting a first sensor
to the mobile vehicle at a maximum lateral distance from said
vertical axis of rotation near a first side. Afterwards, mounting a
second sensor to the mobile vehicle at a maximum lateral distance
from said vertical axis of rotation near a second side. Following,
the method further comprises emitting a first object detecting beam
from the first sensor ahead of the mobile vehicle, emitting a
second object detecting beam from the second sensor ahead of the
mobile vehicle and illuminating an object directly ahead of the
left forward edge and the right forward edge of the mobile vehicle
by one selected from the group consisting of the beam emitted by
the first sensor and the beam emitted by the second sensor. In a
further step of the present method, the first sensor and the second
sensor mounting further includes recessing the first sensor and the
second sensor within a periphery of the mobile vehicle.
[0012] In an alternative embodiment of the method for controlling
the direction of travel of the mobile vehicle further comprises the
steps of mounting a third sensor to the mobile vehicle along the
front, mounting a fourth sensor to the mobile vehicle on the front
to the left of the third sensor, and mounting a fifth sensor to the
mobile vehicle on the front to the left of the fourth sensor.
Additional steps include the fourth sensor emitting an fourth
object detecting beam which forms overlapping beam zone with the
first object detecting beam from the first sensor. Another step
includes emitting a fifth object detecting beam from the fifth
sensor, whereby the fifth object detecting beam from the fifth
sensor forms an overlapping beam zone with a first object detecting
beam from the first sensor.
[0013] Another preferred embodiment of the present method for
controlling the direction of travel of the mobile vehicle further
comprises the steps of collecting data from the overlapping beam
zones about the location of the object, and processing the data
using fusion software. In the alternative, the present method
further includes the step of mounting spaced-apart sensors along
the mobile vehicle to provide more than two overlapping beam zones,
wherein the spaced-apart sensors are configurable to provide
scanning area coverage selected from a range of approximately
190-degrees to approximately 200-degrees. Another alternative
embodiment of the present inventive method further includes the
step of mounting a third sensor near a center of the front of the
mobile vehicle, whereby the third sensor emits a third object
detecting beam comprising a light detecting and ranging (LIDAR)
beam at the object in front of the mobile vehicle and at a
peripherally located object or a wall.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] For a better understanding of the present invention,
reference is made to the below-referenced accompanying drawings.
Reference numbers refer to the same or equivalent parts of the
present invention through several figures of the drawings.
[0015] FIG. 1 is a sensor array mounted on a mobile vehicle.
[0016] FIG. 2A is an illustration of one preferred embodiment of
the present invention depicting the front of a rectangular shaped
mobile vehicle with rounded corners.
[0017] FIG. 2B is an illustration of one preferred embodiment of
the present invention depicting the beam pattern and overlapping
beams for a rectangular shaped mobile vehicle with rounded
corners.
[0018] FIGS. 2C, 2D, and 2E are illustrations of the overlapping
beam zones, for the FIG. 2A embodiment, created by the spaced apart
sensors and the first sensor located at a maximum lateral distance
from a vertical axis of rotation near the first side.
[0019] FIG. 3A is a top view of an acoustically tapered impedance
matching network for one preferred embodiment of the present
invention.
[0020] FIG. 3B is a side view of the acoustically tapered impedance
matching network for one preferred embodiment of the present
invention.
[0021] FIG. 3C is a perspective view of the acoustically tapered
impedance matching network for one preferred embodiment of the
present invention.
[0022] FIG. 4 is a flow diagram depicting the method whereby the
mobile vehicle detects objects.
MODES FOR CARRYING-OUT THE INVENTION
[0023] The present invention provides an improved sensor array for
a mobile vehicle. Accordingly, the primary objective is to provide
an improved sensor array so that the mobile vehicle detects more
accurately the location of objects ahead of the mobile vehicle. In
particular, the primary objective of the present invention is to
provide a mobile vehicle traveling in a forward direction having a
front, a first side, a second side and a vertical axis of rotation
with improved detection ability of objects ahead of the mobile
vehicle.
[0024] FIG. 1 is a sensor array mounted on a mobile vehicle. A
mobile vehicle 10 comprises a sensor array 12. In one preferred
embodiment of the present invention, mobile vehicle 10 is a
unmanned cleaning machine for floors. In the alternative, the
mobile vehicle may be any automatic or semiautomatic machine that
will follow a programmed path with a minimum or no human
supervision. In this preferred embodiment, mobile vehicle 10 is
traveling in the forward direction. In this preferred embodiment,
the forward direction is the Y-direction. Sensor array 12 comprises
a plurality of sensors including a first sensor 16 and a second
sensor 18. In this preferred embodiment of the present invention,
the plurality of sensors further includes sensors 26, 28 and 30
which sensors 26, 28 and 30 are mounted to the mobile vehicle. In
the preferred embodiment of the present invention, first sensor 16,
second sensor 18, and sensors 26, 28 and 30 are selected from a
group consisting of piezoelectric sensors, electrostatic sensors,
magnetorestrictive sensors, light detecting and ranging (LIDAR)
sensors or the like. Further, first sensor 16 is disposed on mobile
vehicle 10 at a maximum lateral distance from vertical axis of
rotation 21 near a first side 15. Second sensor 18 is disposed on
mobile vehicle 10 at a maximum lateral distance from vertical axis
of rotation 21 near a second side 13.
[0025] In this preferred embodiment of the present invention, as
shown in FIG. 1A, sensor array 12 transmits object detecting beams
at an object 20 or at a wall 22. Afterwards, as shown in FIG. 1B,
the object detecting beams are reflected off the object 20 or the
wall 22. Following, sensor array 12 receives these reflected object
detecting beams and uses this information to ascertain position. In
this embodiment, first sensor 16 and second sensor 18, as well as
other sensors 26, 28 and 30 of sensor array 12 are mounted in the
same plane. In one preferred embodiment of the present invention,
sensor array 12 plurality of sensors comprises symmetrically
spaced-apart sensors that are mounted on the mobile vehicle and are
all symmetrically spaced apart and are all located in the same
plane. In an alternative embodiment of the present invention,
sensor array 12 plurality of sensors comprises asymmetrically
spaced-apart sensors that are mounted on the mobile vehicle. In one
preferred embodiment, the asymmetrically spaced-apart sensors are
not located in the same plane so that an engineer may custom design
sensor array 12 to maximize area coverage for a given shape of
mobile vehicle 10.
[0026] FIG. 2A is an illustration of one preferred embodiment of
the present invention depicting a rectangular shaped mobile vehicle
with rounded corners. In particular, this preferred embodiment of
the present invention has the spaced-apart sensors for a mobile
vehicle comprising a rectangular shape with rounded corners are
arranged in a U-shape. The spaced-apart sensors are sonar sensors
which are in this preferred embodiment of the present invention
Polaroid 700 series electrostatic transducers that emit a beamwidth
of 15 degrees. In another preferred embodiment of the present
invention, the spaced-apart sensors comprise sonar sensors each
emitting a beamwidth within the range of approximately 12 degrees
to approximately 15 degrees. However, it should be noted that any
type of piezoelectric (ceramic) or electrostatic, sensor having
beamwidths from four degrees to sixty degrees may be utilized as
the sonar sensors in sensor array 12.
[0027] In this preferred embodiment, there are fifteen sensors in
the sensor array to create the beam pattern coverage with no gaps,
thereby providing approximately 195-degrees of data coverage.
Specifically, there is a first transducer 37 mounted at the
periphery of the sensor array at maximum lateral distance from said
vertical axis of rotation near the first side where the first
transducer points at zero degrees. Further, there is a second
transducer 38 mounted at the periphery of the sensor array at a
maximum lateral distance from said vertical axis of rotation near
the second side where the second transducer points at zero degrees.
There is a third transducer 39 mounted at the center of mobile
vehicle 10 at zero degrees to detect objects directly ahead of
mobile vehicle 10. Furthermore, there are six transducers
positioned at angles relative to zero degrees including a fourth
transducer 40 pointing at -15 degrees, a fifth transducer 42
pointing at -30 degrees, a sixth transducer 44 pointing at -45
degrees, a seventh transducer 46 pointing at -60 degrees, an eighth
transducer 48 pointing at -90 degrees, and a ninth transducer 45
pointing at -75 degrees.
[0028] In addition, there are six transducers positioned from zero
degrees including a tenth transducer 50 pointing at +15 degrees, an
eleventh transducer 52 pointing at +30 degrees, a twelfth
transducer 54 pointing at +45 degrees, a thirteenth transducer 56
pointing at +60 degrees, an fourteenth transducer 58 pointing at
+90 degrees, and a fifteenth transducer 60 pointing at +75 degrees.
More specifically, the first 37 and the second 38 transducers are
preferably situated from each other at zero degrees relative to
each other. The fifteen sensors of the preferred embodiment of the
present invention have a preferable beamwidth of fifteen degrees,
where 7.5 degrees is on each side of the center of a beam. As such,
7.5 degrees on each side of the center of each of the beams creates
a 195-degree field of view.
[0029] FIG. 2B illustrates the overlapping beam zones for the FIG.
2A preferred embodiment of the present invention. In this preferred
embodiment of the present invention, the sensor array includes the
first transducer and the second transducer which provide for the
detection of objects directly ahead of the left and the right edges
of the array. The arrangement of the other transducers, i.e. 40,
42, 44, 46, 48, 45, 50, 52, 54, 56, 58, 60, are mounted to in a fan
shaped array to emit an obliquely beam pattern. First transducer 37
and second transducer 38 are further positioned to act in
conjunction with the fan shaped array providing at least two
overlapping beam zones to provide collision data ahead of the front
of the mobile vehicle. In particular, these overlapping beam zones
creates a stereo field view for detecting objects directly ahead
and at the periphery of the mobile vehicle. In another alternative
preferred embodiment of the present invention is that the sensor
array includes recessing the sensors to provide better detection of
objects and less signal interference.
[0030] FIG. 2C is an illustration of the overlapping beam zones,
for the FIG. 2A embodiment, created by the spaced apart sensors and
the first sensor at a minimum negative X-direction. Specifically,
as shown in FIG. 2C, in one preferred embodiment of the present
invention, the sensor array for the mobile vehicle detects objects
approaching the mobile vehicle within overlapping beam zones. Each
succession time the object is seen, there is created a greater
confidence level that the mobile vehicle is approaching the object.
For example, an object 39, as shown in FIG. 2C having a triangular
surfaces, exclusively detected by transducer 37 emitted object
detecting beam creates a first confidence level 41 that object 39
is within range of the mobile vehicle. Afterwards, as shown in FIG.
2D, when the mobile vehicle travels closer to object 39, object 39
is detected within a first overlapping beam zone created by the
object detecting beam emitted from transducer 40 and the object
detecting beam emitted from transducer 37, creating a second
confidence level 43 that the mobile vehicle is approaching object
39. Following, as shown in FIG. 2E, when the mobile vehicle travels
even closer to object 39, object 39 is detected within a second
overlapping beam zone created by the object detecting beam emitted
by transducer 42 and the object detecting beam emitted from
transducer 37, creating a third confidence level 45 that the mobile
vehicle is ready to contact object 39. In summary, this invention
utilizes multiple overlapping beam zones where the object is
detected to verify that mobile vehicle 10 is approaching the
object. Similar to the first transducer mounted near a first side
detecting objects, the second transducer will detect objects using
overlapping beam coverage with transducers mounted near the second
side of the mobile vehicle.
[0031] To further improve detection of objects, an additional
feature of the present invention is that the sensor fusion software
increases the confidence level for detecting objects. The sensor
array comprises at least two overlapping beam zones wherein the
data is computed through the use of sensor fusion software, whereby
a confidence level for detecting the object ahead of the mobile
vehicle is increased by the software. Furthermore, this above
mentioned transducer arrangement achieve approximately a 195-degree
field of vision. It is another feature of the present invention
that the spaced-apart sensors may be arranged in multiple
configurations to maximize a field of vision of the mobile vehicle.
It is another feature of the present invention that the plurality
of sensors includes spaced-apart sensors for the mobile vehicle are
configurable and reconfigurable by a user so that for different
coverage areas, the spaced-apart sensors may be programmed to
maximize detection of the object.
1TABLE 1 Layout Dimensional Data for 195-degree Sensor Array
Degrees from Y- Direction Course of Length Angle Transducer Number
Motion of the line sensor points 37 (-90) 13.6 0 45 (-84) 13 -75 48
(-76) 12.62 -90 46 (-65) 12 -60 44 (-56) 9.875 -45 42 (-43) 7.625
-30 40 (-23) 6.25 -15 39 0 5.875 0 50 23 6.25 15 52 43 7.625 30 54
46 9.875 45 56 65 12 60 58 76 12.62 90 60 84 13 75 38 90 13.6 0
[0032] Table 1 above describes the mounting instructions for the
FIG. 2A preferred embodiment to achieve approximately a 195-degree
field of vision. The table represents the layout of the sensors
into a U-shaped arrangement that would be suitable for a mobile
vehicle. All line lengths and angles are measured from a midpoint
on a line segment drawn between the two headlight sensors (first
transducer 37 and second transducer 38). This table shows the ideal
locations for a sensor array to be used on a mobile vehicle that is
a cleaning machine such as the Windsor SG28 or the Nilfisk-Advance
Advenger that is to be converted into a mobile robot. It should be
noted that transducer 46 and 48 may be interchanged if it is
desirable to have the ninety degree transducer moved to the extreme
forward position of the mobile vehicle. The individual transducers
don't all need to be located in the same vertical plane. The
individual transducers are ideally situated at zero degrees of a
horizontal plane. Other transducers may be tilted forward or
reversed as desired for detecting objects such as corners, ledges,
stairs, or the like.
[0033] In this alternative preferred embodiment of the present
invention, the spaced-apart sensors for the mobile vehicle
comprising a round shape are arranged in a semi-circular
arrangement. In this alternative embodiment of the present
invention, the sonar array 12 having a plurality of sensors
comprises asymmetrically spaced-apart sensors that are mounted on
the mobile vehicle. In this alternative embodiment, the
asymmetrically spaced-apart sensors are not located in the same
plane. In another alternative embodiment, the asymmetrically
spaced-apart sensors are located in the same plane. In yet another
alternative the spaced apart sensors may be symmetrically
spaced-apart sensors that may or may not be located in the same
plane. In this manner, an engineer may custom design the sensor
array to maximize area coverage for a given shape of a mobile
vehicle.
[0034] FIGS. 3A and 3B are respectively a top view of an
acoustically tapered impedance matching network and a side view
along the A-A section for one preferred embodiment of the present
invention. In this alternative embodiment of the present invention,
impedance tapering for the sensors of the array increases the
detection accuracy of the object. Specifically, as shown in FIG.
3A, a recess-mounted sensor 51 within a first acoustically tapered
matching network 53 with a mobile vehicle periphery 56. As shown in
FIG. 3B, recess-mounted sensor 51 has a beamwidth 55 that is
approximately 15 degrees and the cone 57 has a angle of
approximately 30 degrees. In this preferred embodiment of the
present invention for minimum reflection of wave energy, angle of
the cone 57 is required to be greater than a beamwidth 55. In this
preferred embodiment of the present invention the first
acoustically tapered impedance matching network comprises an
conically tapered horn. By tapering the acoustical wave,
transmitted waves from recessed mounted sensor 51 will not reflect
back from an intersection of the acoustically tapered impedance
matching network and a surface of the mobile object. As such, the
transmitted waves will not reflect back to recess mounted sensor
51, causing the received signals to be interfered with or
distorted, thereby preventing inaccurate measurements of the object
(not shown in the Figure). FIG. 3C displays a perspective view of
the recess mounted sensor 51. Other sensors may be recess mounted,
such as a second acoustically tapered impedance matching network
comprises an conically tapered horn.
[0035] Furthermore, recessed-mounted senor 51 will allow the
objects closer to the mobile vehicle to be detected more accurately
than is possible without recess mounting. For example, the
recess-mounted sensor 51 allows the beam with the mobile vehicle to
be pointed at a sharper angle, i.e. closer to a periphery of the
mobile vehicle, so that when the object gets near to the mobile
vehicle, the object is still detectable. In contrast, a
surface-mounted sensor (not shown in Figure) emitted a beam with an
angle that depends on the periphery of the mobile vehicle. In this
preferred embodiment, a recess-mounted sensor mounting angle has
more options.
[0036] FIG. 4 is a flow diagram depicting the method whereby the
mobile vehicle detects objects. In particular, a method for the
present invention is disclosed for controlling a direction of
travel of a mobile vehicle having a front and a vertical axis of
rotation, traveling in a forward direction comprising mounting a
first sensor to the mobile vehicle at a maximum lateral distance
from said vertical axis of rotation and mounting a second sensor to
the mobile vehicle at a maximum lateral distance from said vertical
axis of rotation. Afterwards, method includes step 60 emitting an
object detecting beam from the first sensor ahead of the mobile
vehicle, step 62 emitting an object detecting beam from the second
sensor ahead of the mobile vehicle; and step 64 illuminating an
object ahead of the mobile vehicle by one selected from the group
consisting of the beam from the first sensor and the beam from the
second sensor. In an alternative embodiment of the present
inventive method, the method further includes recess mounting the
first sensor and the second sensor within a periphery of the mobile
vehicle.
[0037] To increase accuracy of detecting objects, an alternative
embodiment of the method is disclosed for controlling the direction
of travel of the mobile vehicle further comprising step 66 mounting
a third sensor to the mobile vehicle along a center of the front of
the mobile vehicle, step 68 mounting a fourth sensor to the mobile
vehicle to the left and adjacent to the third sensor. Additional
step 70, in an alternative embodiment, includes emitting an object
detecting beam from the fourth sensor, whereby the object detecting
beam from the fourth sensor forms a first overlapping beam zone
with the object detecting beam from the first sensor. Another
additional step 72, in another alternative embodiment, includes
mounting a fifth sensor to the left and adjacent to the fourth
sensor, emitting an object detecting beam from said fifth sensor.
The object detecting beam from the fifth intersects with said
object detecting beam from said first sensor to create a second
overlapping beam zone. These first and second overlapping beam
zones being detected in succession creates a increasing confidence
level that the mobile vehicle will collide with the mobile vehicle.
Similar overlapping beam zones are created with the second sensor
and object detecting beams emitted by other transducers.
[0038] Another preferred embodiment of the present method for
controlling the direction of travel of the mobile vehicle further
comprises the steps of collecting data coverage about the location
of the object, and processing the data using fusion software. The
fusion software increases the confidence of the position of the
object ahead of the mobile vehicle. Fusion software allows a user
to fuse the recording of the object's position as the mobile
vehicle approaches the object using multiple zones of coverage. For
example, as the mobile vehicle approaches the object, the object
will pass through multiple increasingly closer overlapping beam
zones, increasing the confidence level that the mobile vehicle is
approaching the object.
[0039] As such, this multiple detection by overlapping beam zones
allows a user to generate more confidence of the position of the
object so that the mobile vehicle can maneuver around it. In other
words, the fusion software represents a method of positively
identifying the actual position of the object with a high degree of
certainty. By fusing the beam data, the computed detection area
with be only -1 dB. By comparison, the normal detection of the
object would be only -3 dB.
[0040] In the alternative, the present method further includes the
step of mounting spaced-apart sensors along the mobile vehicle to
provide more than two overlapping beam zones, wherein the
spaced-apart sensors are configurable to provide scanning area
coverage selected from the range of approximately 190-degrees to
approximately 200-degrees.
[0041] Another alternative embodiment of the present inventive
method further includes the step of mounting a third sensor near a
center of the front of the mobile vehicle, whereby the third sensor
emits a third object detecting beam comprising a light detecting
and ranging (LIDAR) beam toward the object in front of the mobile
vehicle and toward a peripherally located object or wall.
[0042] Information as herein shown and described in detail is fully
capable of attaining the above-described object of the invention
and the present preferred embodiment of the invention, and is,
thus, representative of the subject matter which is broadly
contemplated by the present invention. The scope of the present
invention fully encompasses other embodiments which may become
obvious to those skilled in the art, and is to be limited,
accordingly, by nothing other than the appended claims, wherein
reference to an element in the singular is not intended to mean
"one and only one" unless explicitly so stated, but rather "one or
more." All structural and functional equivalents to the elements of
the above-described preferred embodiment and additional embodiments
that are known to those of ordinary skill in the art are hereby
expressly incorporated by reference and are intended to be
encompassed by the present claims.
[0043] Moreover, no requirement exists for a device or method to
address each and every problem sought to be resolved by the present
invention, for such to be encompassed by the present claims.
Furthermore, no element, component, or method step in the present
disclosure is intended to be dedicated to the public regardless of
whether the element, component, or method step is explicitly
recited in the claims. However, one skilled in the art should
recognize that various changes and modifications in form and
material details may be made without departing from the spirit and
scope of the inventiveness as set fourth in the appended claims. No
claim herein is to be construed under the provisions of 35 U.S.C.
.sctn. 112, sixth paragraph, unless the element is expressly
recited using the phrase "means for."
INDUSTRIAL APPLICABILITY
[0044] The present invention relates to a sensor array for a mobile
vehicle. More particularly, this invention applies industrially to
a sensor array for a mobile vehicle traveling in the Forward
direction having a first sensor and a second sensor. The first
sensor is mounted to the mobile vehicle at a maximum lateral
distance from said vertical axis of rotation. The second sensor is
mounted to the mobile vehicle at a maximum lateral distance from
said vertical axis of rotation. The first and the second sensor are
applied industrially to illuminate objects directly ahead the
mobile vehicle and create zones of overlapping beam coverage with
other obliquely emitted beams from the mobile vehicle to improve
the accuracy of detecting approaching objects.
* * * * *